Stop-Signal Task
The Stop-Signal Task (Logan, Cowan & Davis, 1984) quantifies response inhibition via SSRT. Verbruggen et al. (2019) eLife consensus guide is the contemporary authoritative specification.
Intermediate: 160 trials, 1.2 s stimuli.
You'll see an arrow — press ← or → based on its direction. On ~25% of trials a STOP signal (red) appears shortly after — when that happens, withhold the press. SSD adapts to keep stopping rate around 50%.
History
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References: Logan, Cowan & Davis (1984); Verbruggen et al. (2019) eLife; Williams et al. (1999).
Stop-Signal · scientific basis
The Stop-Signal Task was introduced by Logan, Cowan & Davis (1984) based on a horse-race model. Verbruggen et al. (2019) eLife consensus guide integrates 40+ years of research and is the contemporary authoritative reference for SSRT estimation.
Expert-mode parameters
These are the standard parameters from the canonical paradigm (used by the "Expert" difficulty).
| Parameter | Standard value | Source |
|---|---|---|
| Go task | 2-choice RT (left/right arrow) | Verbruggen 2019 |
| Stop ratio | 25% | Verbruggen 2019 |
| Initial SSD | 250 ms | Verbruggen 2019 |
| Staircase step | ±50 ms | Verbruggen 2019 |
| Target stop rate | ~50% | Verbruggen 2019 |
| Total trials | 256 (≥60 stop trials) | Verbruggen 2019 |
| SSRT method | integration method | Verbruggen 2019 |
Healthy-population norms (by age)
Primary outcome is SSRT (stop-signal reaction time, lower is better). SSRT Excellent = mean − 1 SD. Derived from Verbruggen 2019 eLife consensus methodology and Williams 1999 lifespan developmental sample (n≈275, ages 6-81); SSRT is shortest in adulthood (~215 ms), longer in children and older adults. Assessment mode matches the band to your actual age.
| Age band | SSRT Excellent (ms) | SSRT Mean (ms) | Go RT Mean (ms) | Evidence |
|---|---|---|---|---|
| 8-9 | ≤ 230 | ~310 | ~710 | moderate-weak |
| 10-11 | ≤ 215 | ~285 | ~640 | moderate-weak |
| 12-13 | ≤ 200 | ~260 | ~580 | moderate-weak |
| 14-15 | ≤ 185 | ~240 | ~540 | moderate |
| 16-17 | ≤ 175 | ~225 | ~510 | moderate |
| 18-24 | ≤ 165 | ~215 | ~480 | moderate |
| 25-34 | ≤ 165 | ~215 | ~480 | moderate |
| 35-44 | ≤ 170 | ~220 | ~490 | moderate |
| 45-54 | ≤ 170 | ~225 | ~510 | moderate |
| 55-64 | ≤ 175 | ~235 | ~550 | moderate-weak |
| 65+ | ≤ 180 | ~245 | ~600 | moderate-weak |
Standard output metrics
- ·SSRT — Stop-signal RT (primary; lower is better)
- ·Mean SSD — Staircase convergence point
- ·Go RT — Baseline choice RT
- ·p(respond|signal) — Should ≈ 0.50 (validity check)
- ·Go error rate — Should be <10% (validity)
Citations
- Logan, G. D., Cowan, W. B., & Davis, K. A. (1984). On the ability to inhibit simple and choice reaction time responses: A model and a method. J Exp Psychol Hum Percept Perform, 10(2), 276-291. DOI
- Verbruggen, F., Aron, A. R., Band, G. P. H., et al. (2019). A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task. eLife, 8, e46323. DOI
- Williams, B. R., Ponesse, J. S., Schachar, R. J., Logan, G. D., & Tannock, R. (1999). Development of inhibitory control across the life span. Dev Psychol, 35(1), 205-213. DOI
- Schachar, R. J., & Logan, G. D. (1990). Impulsivity and inhibitory control in normal development and childhood psychopathology. Dev Psychol, 26(5), 710-720. github.com
All reference ranges come from published peer-reviewed literature. For personal training reference only — not a medical diagnosis. Full methodology: docs/PARADIGMS.md.
This tool is for educational and entertainment purposes only and does not constitute medical advice or a clinical diagnosis.